Aim

Sediment disturbances are important threats affecting marine biodiversity, but the variety of biological responses has not yet been synthesized. Here, we collate all available information to compare the extent of impacts across different taxonomic groups, habitat types and pathways of impact (light attenuation, suspended sediment and sedimentation).

Location

Global.

Time period

Data collected from 1979 to 2017.

Major taxa studied

Methods

We used meta‐analyses to evaluate the effects of sediments across 842 observations found in 110 publications. We also evaluated some of the biological and methodological factors that could explain the variable effects observed in different studies.

Results

We found a significant negative effect of sediments on behavioural responses of species, reproduction and recruitment processes, the morphology of organisms, physiology, community abundance and diversity, and species interactions. In contrast, the overall effect on the abundance of individual species was statistically non‐significant and there was a strong positive effect on abundance for sponge and polychaete species. Many individual studies described physiological effects on coral reefs, but the effects on the diversity of soft‐bottom and coral reef communities were particularly detrimental. Phototrophic species were generally more negatively impacted by sediments than heterotrophs, driven by strong physiological responses in crustose coralline algae and seagrasses. Additionally, species with limited mobility were more vulnerable to sediment disturbances than highly mobile species. Sedimentation alone triggered more consistently negative effects on most biological responses than light depletion and suspended sediments. We found evidence for increased impacts on community diversity when more than one pathway of impact was present, indicating that these disturbances can disrupt whole ecosystems.

Main conclusions

Our meta‐analysis provided, for the first time, strong quantitative support of negative effects of sediments on marine biodiversity. Taxonomic groups, habitat types and life‐history characteristics were most influential in determining the biological responses to sediment disturbances, highlighting the importance of an ecosystem‐based approach when fully accounting for the impacts of sediments.

Deep-sea ecosystems are the most extensive on Earth and provide key goods and services for human well-being, such as genetic resources and climate regulation. Maintaining the sustainable functioning of the global biosphere therefore requires protection of deep-sea ecosystems, particularly because these ecosystems face major changes related to human and climate-induced impacts. Although we lack data to evaluate the spatial scale of degraded deep-sea habitats, numerous studies document human impacts on the whole ocean. However, protection alone can be insufficient to reverse habitat degradation in the deep sea. Scientifically, deep-sea restoration actions may be feasible, but whether such actions will achieve sustainability goals when applied at broad spatial scales of impact remain questionable. Successful application of most restoration efforts will first require a deeper understanding of biodiversity and functioning of deep-sea ecosystems, and better knowledge of ecosystem resilience and recovery rates of deep-sea fauna. In addition to limited data availability, expensive technologies (with estimated costs up to millions of dollars ha−1) represent a major obstacle to large-scale deep-sea restoration, but international cooperation (like a stronger collaboration between industry and scientists belonging to the academia) could significantly reduce this operational cost. Future deep-sea ecosystem restoration could offer an important business opportunity for technological development and application and an investment in natural capital for a new and competitive blue-growth sector.

The importance of institutions in structuring access to resources is well documented. However, despite the depth of the research, few studies have examined this systematically at the level of an individual fishing activity or, more specifically, within a women's fishery. This paper explores how fisherwomen access octopuses in a small-scale fishery in Mozambique, within a context where an increasing number of conservation initiatives are targeting women's fisheries and could potentially affect fisherwomen's access. The study was conducted within the Quirimbas National Park (QNP) in Cado Delgado, the northern most province of Mozambique. Combining ethnographic fieldwork and an institutional access map as a conceptual framework, this paper provides insight into the multiple institutions that structure how octopus fishing is organised and performed by fisherwomen. The access map reveals the dominant role local normative institutions play in influencing fisherwomen's access to income from fishing for octopus. Purdah, the religious practice of securing a woman's honour, is identified as a key restraining institution that is enforced through unequal gender relations. The paper encourages an understanding of the institutional context of fishing practices in order to promote access in small-scale fisheries (SSFs) to ensure fishers continue to benefit from the fishery in the face of management. The paper concludes that a greater appreciation of power relations – encapsulated in this study by gender relations – is required to further develop institutional analyses in small-scale fisheries policies and management.

Oil spills are a widespread problem in the marine environment and can have extensive acute and chronic adverse impacts to resident and migratory biota. On 19 January 1996, the North Cape oil tanker caught fire and grounded on the coast of Rhode Island resulting in the spill of 828,000 gal (3134 metric tonnes) of home heating oil. It resulted in the estimated death of nearly 2300 birds, including a projected 402 common loons (Gavia immer) and 12 red-throated loons (Gavia stellata). Based on existing demographic data, a resource equivalency analysis (REA) calculated that the total loss, as measured through dead adults and their foregone young over their expected lifetimes, was 2920 discounted loon-years. To generate compensatory loon years, it was initially estimated that 25 common loon nests would need protection from development for 100 years. Following a $3 million settlement with the parties responsible for the spill, we conducted surveys to identify the highest quality breeding loon habitat for protection. Monitoring efforts included 184 loon territories from 2000 to 2009, representing 866 loon territory-years on 70 lakes in four regions of Maine. To evaluate restoration effectiveness, an updated REA was conducted using productivity data collected from these surveys. Results from the updated REA indicated that were these site-specific data available when the REA was originally generated, 70 nests would have been required to offset the lost loon-years – this project permitted the protection of 119 nests. Future REAs should incorporate site specific productivity data whenever possible to most accurately scale restoration to injury. Ranking lake habitat quality further optimizes restoration effectiveness. Our results indicate breeding success was highest on 24–81 ha lakes and that emphasizing protection of lakes with loon territories in this size class is optimal. Our results demonstrate a need for site-specific restoration plans to achieve the greatest restoration benefits.

This paper presents an analysis of key elements contributing towards current and future prospects for governance in two MPAs in the Pacific Region of Guatemala. The paper follows the Marine Protected Area Governance (MPAG) empirical framework through the use of economic, interpretative, knowledge, legal and participative incentives that assess the effectiveness of governance. The first MPA is the Multiple Use Area of Monterrico that is governed through a co-management approach by the Centre of Conservation Studies of the University of San Carlos de Guatemala (CECON-USAC), whilst the second is Guatemala's only privately-owned marine protected area, La Chorrera-Manchón Guamuchal Reserve. The results highlight that the differences in the way they are governed have significantly shaped the effectiveness of governance. In the case of Monterrico, the limited state capacity and cross-jurisdictional coordination among stakeholders has resulted in weak economic and legal incentives, where efforts have failed to develop the necessary participatory approach to management. As a result, environmental degradation and increasing urban development is apparent, which have proven difficult to manage by the park management authority. Conversely, La Chorrera-Manchón Guamuchal has developed a governance approach based on local community involvement, which has proven successful for conservation and management initiatives for the reserve. Management is characterized by strong leadership, which has proven to be the underlying difference in both MPAs. However, the fate of the reserve is uncertain, as there is no long-term planning for success. Future prospects for effective governance are recommended, where efforts should primarily foster state involvement and political will.

Primarily applied to land-based resources, academics have utilised the concept of commodity frontiers to understand the expansionary nature of capitalism, and the ways that existing hegemonies and systems of control and access of resources are challenged and altered. Following recent calls to expand this concept to marine spaces, this paper has used political ecology and in particular its focus on power and access to explore how capitalist expansion has impacted the means and methods of access to key resources in a small-scale marine fishing community in Ghana. The findings of the paper are based upon an eight-month field visit to Aboadze in the Western Region of Ghana, a traditional fishing community that is considered a ‘closing’ frontier, on account of recent research that suggests the small-pelagic fish stocks will collapse within a decade. The findings of the paper show that accessing fish and other necessary resources such as gear and capital has become increasingly difficult as stocks continue to dwindle, and those living in the case study community have to resort to unsustainable fishing methods in order to survive. The paper also finds that the vulnerability caused by decades of overfishing by foreign trawlers is felt disproportionately by certain members of the community, compounding existing vulnerabilities that arise through gender and class.

A cocktail of land-based sources of pollution threatens coral reef ecosystems, and addressing these has become a key management and policy challenge in the State of Hawaiʻi, other US territories, and globally. In West Maui, Hawaiʻi, nearly one quarter of all living corals were lost between 1995 and 2008. Onsite disposal systems (OSDS) for sewage leak contaminants into drinking water sources and nearshore waters. In recognition of this risk, the Hawaiʻi State Department of Health (DOH) is prioritizing areas for cesspool upgrades. Independently, we applied a decision analysis process to identify priority areas to address sewage pollution from OSDS in West Maui, with the objective of reducing nearshore coral reef exposure to pollution. The decision science approach is relevant to a broader context of coastal areas both statewide and worldwide which are struggling with identifying pollution mitigation actions on limited budgets.

The community of species, human institutions, and human activities at a given location have been shaped by historical conditions (both mean and variability) at that location. Anthropogenic climate change is now adding strong trends on top of existing natural variability. These trends elevate the frequency of “surprises”—conditions that are unexpected based on recent history. Here, we show that the frequency of surprising ocean temperatures has increased even faster than expected based on recent temperature trends. Using a simple model of human adaptation, we show that these surprises will increasingly challenge natural modes of adaptation that rely on historical experience. We also show that warming rates are likely to shift natural communities toward generalist species, reducing their productivity and diversity. Our work demonstrates increasing benefits for individuals and institutions from betting that trends will continue, but this strategy represents a radical shift that will be difficult for many to make.

The present study aims to provide a conceptual framework to help practitioners to improve the quality of recreational waters near estuary, which may be affected by untreated wastewater from Combined Sewer Overflows (CSOs). When CSOs are activated, the concentration of bacteria (e.g., Enterococci and E. coli) in estuary increases, thereby resulting in a potential health threat to swimmers. Here, the bacterial exposure is evaluated using physically-based stochastic model for contaminant transport, while human health risk is determined by Quantitative Microbial Risk Assessment (QMRA). Based on human health risk framework, we quantify the Carrying Capacity (CC) of the recreational water body. Such an indicator is defined as the number of swimming individuals that can be sustained in a beach resort with an acceptable risk threshold. The CC increases by dilution processes and by reduction of the source concentration, which in turn depends on the improvements in the sewage system. The presented approach can be a useful screening tool for policy-makers and other stakeholders, thereby providing a potential solution to the trade-off between economic development and the sustainable ecosystem in coastal areas.

Managing coastal areas under an Ecosystem Based Approach–Marine Spatial Planning framework acknowledges the complexity associated with the need to address multiple environmental and socioeconomic issues. The development of efficient management plans is critical to the implementation success of the framework; in this regard, unresolved challenges remain for measuring the effectiveness of planning plans and monitoring implementation progress. This paper describes the development of a Bayesian Belief Network as a prototype Decision Support Tool to assist coastal planning in the catchment areas of the Sydney Harbour, New South Wales, Australia. The model was co-designed with local managers, underpinned by the Drivers-Pressures-States-Impacts-Responses analytical framework to identify key coastal cause-effect relationships, and by the Recreational Opportunity Spectrum framework to account for significant recreational areas. The Bayesian Belief Network was structured on a conceptualisation of the relationships between key pressures affecting coastal management targets (biological areas and human activities) and their impacts on the state of the variables, with emphasis on the beach ecosystem. The socio-economic component of the model consists of predictive socio-economic modelling on preferred beach activities, the assessment of beach recreational settings, and a beach quality survey. Conditional probability tables were derived from local and regional databases. The model structure allows decision makers enhanced understanding of key interactions between management variables, assessment of management scenarios, and increased accountability of planning decisions. Future work on the prototype could expand the model to become a Bayesian Decision Network, through the integration of proposed management actions and their utilities, thereby helping managers identify optimal decisions.